At first sight, Bradley Strawser resembles a humanities professor from central casting. He has a beard, wears jeans, quotes Augustine and calls himself, only half in jest, a hippie. He opposes capital punishment and Guantánamo Bay, calls the Iraq invasion unjust and scorns neo-conservative foreign policy hawks. "Whatever a neocon is, I'm the opposite."

His office overlooks a placid campus in Monterey, an oasis of California sun and Pacific zephyrs, and he lives up the road in Carmel, a forested beauty spot with an arts colony aura. Strawser has published works on metaphysics and Plato and is especially fond of Immanuel Kant.

Strawser is also, it turns out, an outspoken and unique advocate for what is becoming arguably the US's single most controversial policy: drone strikes. Strawser has plunged into the churning, anguished debate by arguing the US is not only entitled but morally obliged to use drones.

"It's all upside. There's no downside. Both ethically and normatively, there's a tremendous value," he says. "You're not risking the pilot. The pilot is safe. And all the empirical evidence shows that drones tend to be more accurate. We need to shift the burden of the argument to the other side. Why not do this? The positive reasons are overwhelming at this point. This is the future of all air warfare. At least for the US."

His forceful defence of the military use of unmanned aerial vehicles (UAVs), as drones are also called, is largely the reason he has landed a tenure-track post as assistant professor of philosophy at Monterey's Naval Postgraduate School, an elite college which gives masters and PhD courses to military officers, academics and policymakers.

The post, part of the school's defence analysis department, underlines a belief that drones and military ethics are set to become ever more fraught topics in Washington, Islamabad, Kabul and other capitals. "The school wanted a voice in that conversation, so they hired me. My job talk was on the ethics of drones. It's what I've become most known for."

Strawser, 33, a married father of two young children, just moved here from his previous post as resident research fellow at the Stockdale Center for Ethical Leadership in Annapolis, Maryland. He has yet to unpack boxes and properly furnish his office but there is little doubt he will be a vocal, and in some quarters reviled, voice in the debate.

Unmanned drones will be on the agenda at the Anglo-French summit on defence co-operation. Photograph: Sipa Press/Rex Features

He has edited a book – Killing By Remote Control: The Ethics of an Unmanned Military – to be published soon by Oxford University Press. Drones, controlled by air force operators in Nevada and New Mexico who track targets on screens, have become Washington's main weapon against Islamist militants in Afghanistan, Pakistan, Somalia and Yemen. The US reportedly has 7,000 drones operating – more than manned aircraft – and 12,000 more on the ground.

Strained relations

The American Civil Liberties Union estimates strikes have killed 4,000 people, a significant number of them civilians, since 2002, with the tempo sharply accelerating under President Barack Obama.

Figures from the London-based Bureau of Investigative Journalism show that CIA drones stuck Pakistan 75 times in 2011, causing up to 655 fatalities, including as many as 126 civilians.

Pakistani authorities reported that 19 people died last Friday in an attack in the Dattakhel region in North Waziristan, further straining relations with Washington which has ignored protests from Islamabad.

Christof Heyns, the UN special rapporteur on extrajudicial killings, recently said some strikes may constitute "war crimes" and that they would encourage other states to flout long-established human rights standards. Jimmy Carter, the former president, echoed unease amid reports detailing White House "kill lists".

"The US can no longer speak with moral authority on human rights," Carter said.

Strawser, who calls himself "doveish" on foreign policy, has proven an unexpected and forthright champion for the barrage of Hellfire missiles. His background may partly explain it. He is a self-described "army brat", the son of an academic father who worked on air force computer systems, and grew up on air force bases.

After obtaining a bachelor's degree in history and English, he followed his father's footsteps and served seven years in the air force as an administrator – he did not see combat – before taking graduate night courses and "falling in love" with philosophy. He taught ethics courses while obtaining a PhD. His dissertation was on just war and moral responsibility, a recurring topic in his work.

Strawser now lives in the same town as Clint Eastwood and may soon become known as philosophy's answer to Dirty Harry. With an affable tone, he methodically blasts objections to the drone strikes taking place 7,000 miles away. "When I started studying this topic I didn't know this would be my conclusion. But that's where my analysis led me."

'What matters to me is whether the cause itself is justified'

One objection sometimes posited is that there is something wrong or ignoble in killing through such lopsided asymmetry. "I share the kind of gut feeling that there's something odd about that. But I don't see the ethical problem. What matters to me is whether the cause itself is justified. Because if the operation is justified and is the right thing to do – and by the way I'm not claiming all US military strikes are – then asymmetry doesn't matter."

In an analogous case of police officers in a shootout with bank robbers you would want the former to have bullet-proof vests, Strawser says. "It's a moral gain, not a moral problem."

Another objection is that risk-free remote killing degrades traditional conceptions of valour. "You hear that from within the military and the average American on the street. That's a real concern, I share it. But when you speak to these pilots – or operators, there's a debate over the correct term - they'll tell you it's a very stressful job. Several of them have had PTSD. Think about what they see all day … you're watching people die on your screen."

"I think it does take a certain type of intellectual bravery and perhaps some moral courage to fly drones in good conscience and believe in the mission you're doing. We are called cowards for this. Coward or not, if it's the right thing to do, to not risk a soldier when you don't have to, and you think the cause is just, I just feel that that normative force is too powerful to overcome."

Strawser makes an analogy of not risking human bomb disposal teams if robots could do their job just as well.

A US drone flying out from Kandahar airfield in Afghanistan. Photograph: Kirsty Wigglesworth/AP

Strawser said a third objection, that drones encouraged unjust operations by reducing the financial and political cost to the US, was serious but surmountable. "There could be an upside. There are cases when we should go to war and we don't, especially in humanitarian case like Rwanda. More generally, this objection is highly predictive about our future moral behaviour. It's like saying: I'm going to do something which I know is wrong now to prevent me from doing something wrong later."

Strawser says cases where drone strikes allegedly killed innocents would be unjustified, but did not render the technology illegitimate. "If the policy to begin with is wrong then of course we shouldn't do it. It's irrelevant if we use drones, a sniper rifle or a crossbow." He says he considers poison gas and nuclear weapons inherently wrong because they did not discriminate – unlike drones.

"The question is whether drones will tempt us to do wrong things. But it doesn't seem so because we have cases where drones were used justly and it seems they actually improve our ability to behave justly. Literally every action they do is recorded. For a difficult decision (operators) can even wait and bring other people into the room. There's more room for checks and oversights. That to me seems a normative gain."

Straswer says he understands why many shuddered over revelations of the so-called White House "kill lists" but believes it, in fact, shows accountability at the highest level, unlike Abu Ghraib, when authorities pinned blame on lower ranks.

He acknowledges why many called the strikes assassinations, or extra-judicial killings, but says they could be deemed "necessary and proportionate" to save lives. "People can make themselves liable to be killed by a drone strike in defence of the non-liable people they are threatening."

Strawser is at pains to stress he is no hawk. But if a particular operation was just, and if using a drone could avert risk to a pilot without compromising the operation, the US had a duty to use drones, he says.

"The cost-savings, the ethical gain by better protecting the war fighter, increased capability: add all that together."

In the fall, Strawser will start teaching military ethics to officers from the US services and those from allied militaries around the world. He worries that hawks could adopt his arguments about drones without taking account of his caveats. "It's the thought that keeps me up at night. Because if my arguments were going to be misused.." The voice trails off and he shakes his head.

"In that case you could say maybe I should just keep quiet."

Silence is unlikely. Strawser and the Naval school are mutually delighted with the appointment. "I wanted to be a working philosopher and here I am. Ridiculous good fortune."

• Amendments were made to the headline, subheading and text of this article on 4 September 2012. The original headlines were misleading in terms of the arguments expressed by Bradley Strawser in the article. In addition, the article stated that he would be teaching generals and admirals in a newly created post. This has been corrected.